Pavement Design & Materials Flashcards
6 cards from real CTE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Pavement Design & Materials flashcards as text
What is the purpose of 'tack coat' in asphalt pavement construction?
Answer: To bond successive asphalt layers together and prevent slippage between them
Tack coat is a thin application of diluted asphalt emulsion applied to an existing pavement surface before placing a new HMA layer to create adhesive bond and prevent interfacial slippage.
What pavement distress index is used by most US highway agencies for network-level pavement management?
Answer: Pavement Condition Index (PCI)
The Pavement Condition Index (PCI), developed by the US Army Corps of Engineers, rates pavement surface condition from 0 (failed) to 100 (perfect) based on type, severity, and quantity of distresses.
What does 'densification' refer to in HMA pavement compaction?
Answer: Reducing air voids through roller compaction to achieve target density and pavement performance
Densification is the process of reducing air voids in hot-mix asphalt through steel wheel and pneumatic roller compaction to achieve 92–96% of maximum theoretical density for optimal performance.
What is the primary function of a 'permeable base' or 'open-graded drainage layer' beneath pavement?
Answer: To quickly drain water from beneath the pavement to prevent moisture damage and pumping
Permeable/open-graded drainage bases rapidly remove infiltrated water from beneath pavement structures, preventing moisture-induced distress, pumping, and freeze-thaw damage in the subbase.
In the Superpave mix design system, what is the 'design number of gyrations' (Ndesign) based on?
Answer: The anticipated traffic loading level (ESALs) over the design life
Superpave Ndesign specifies the number of gyrations in the SGC used to compact mix design samples, selected based on the design traffic level in ESALs — higher traffic requires more gyrations for denser compaction.
What is 'reflective cracking' in asphalt overlays and how is it mitigated?
Answer: Propagation of existing cracks or joints from an underlying pavement up through new overlay; mitigated by interlayer systems, thick overlays, or crack treatment
Reflective cracking occurs when cracks or joints in the existing pavement propagate upward through an asphalt overlay due to differential movement; mitigation includes interlayer systems (SAMI, geosynthetics), crack/seat, or full-depth reclamation.